You could just pick up bonded filter. Much cheaper, just cut out the size you need. That way you can buy a container of carbon and replace it your self every week. Run pads for two to three months, and run multiple at a time so that at any given point there is enough on each pad.
All of my tanks have bio wheels of some size and I always keep a cartridge in there. The wheel for sure helps, but you can never give your bacteria enough space to live or have too much filtration.
55gPLANTED:Rainbows/Loaches/Garras|30gVIV:Crestie|20gL:Leos|10g:Pearl Fighter|5g:Betta|5gChi:Spark Gourami/Badis|5g:ADF|2.5g:Betta|2.5g:Betta|